1. Field of the Invention
The present invention relates to an optical pointing device and, more particularly, to an optical pointing device capable of preventing light emitted from a light source from dazzling user's eyes when a user turns the optical pointing device upside down.
2. Description of the Related Art
Generally, an optical pointing device, one of peripheral devices of a computer, is a device for controlling a position of a curser displayed in a display device of the computer using the reflection amount of light irradiated from a light source. In particular, since the optical pointing device can more precisely detect movement of a user's hand and can be smoothly moved in comparison with a conventional ball pointing device, the optical pointing device has been more generally used.
Hereinafter, the structure of a general optical pointing device will be described in conjunction with FIG. 1A.
First, the optical pointing device generally includes a base plate 10, a lens 30 disposed on the base plate 10, and a circuit board 70 disposed on the lens 30.
The base plate 10 has a through-hole 15 formed at its center, and a positioning projection 20 for fixing a position of the circuit board 70 at its one side.
In addition, the lens 30 is mounted on the through-hole 15 formed at the center of the base plate 10.
Further, the circuit board 70 is fixed to one side of the positioning projection 20 formed at the base plate 10 to be disposed on the lens 30. An optical sensor 50 and a light source 40, such as a light emitting diode are disposed on the circuit board 70, and the optical sensor 50 is electrically connected and fixed to an upper surface of the circuit board 70. Then, a fixing clip 60 is installed on the circuit board 70 to prevent the abovementioned components from shaking due to external impact and vibration.
Hereinafter, an operation of the optical pointing device will be described. First, when light is irradiated from the light source 40, the light is reflected by a bottom surface of an object. Then, the light reflected from the bottom surface is collected through the lens 30, and the collected light is input to a sensor 50 installed at the circuit board 70. The sensor 50 for receiving the light detects movement of the pointing device relative to x and y-axes on the basis of variations of the amount of the received light, and outputs a predetermined signal according to the variations to transmit it to an MCU (not shown). Next, the signal output from the sensor 50 is transmitted to a computer main body (not shown) together with data input from an input part (not shown) such as buttons and a scroll wheel.
However, in general cases, since the optical pointing device is used in contact with the bottom surface 190, a user cannot directly see the light irradiated from the optical pointing device. However, as shown in FIG. 1B, when the user intentionally turns the optical pointing device upside down to separate the base plate 10 from the bottom surface, the light irradiated from the light source is not reflected into the optical pointing device and the user can directly see the light so that the light dazzles the user's eyes. In addition, even when the optical pointing device is in an inactive state, the light irradiated from the light source is reduced, but the light source still irradiates light sufficient to dazzle the user's eyes.